CVGHM reported that seismicity at Seulawah Agam increased during 27 December-2 January. Visual observations were prevented due to fog, although on 2 January scientists observed a new solfatara that produced roaring noises and was within 20 m of van Heutsz Crater on the NNE flank. The Alert Level was raised to 2 (on a scale of 1-4) on 3 January.

Seulawah Agam (also known as Seuleuwah Agam) volcano, one of three active stratovolcanoes in the Aceh province (>5 million inhabitants), is located at the NW tip of Sumatra. Seulawah Agam has two craters, van Heutsz (Heszt), the most active crater at an elevation of 714 m on the N flank, and Simpago on the S flank. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) reported that activity at Seulawah Agam is generally characterized by white plumes rising ˜1 m from the crater. Seulawah Agam has remained non-eruptive through at least 2 January 2013.

Historical data indicated that Seulawah Agam volcano last erupted 12-13 January 1839 on its NNE flank (van Heutsz crater). Prior to that, an eruption occurred in 1510 (˜10 years), also on its NNE flank.

During April to August 2010, the seismic data suggested increased activity overall, with marginal fluctuation. On 1 September 2010, CVGHM raised the Alert Level from I to II and restricted visitors from approaching the crater within a 3-km radius. [The 4-level Indonesian Alert Level Scale is as follows: I - Normal (green); II - Waspada or Alert (yellow); III - Siaga or Standby (orange); and IV - Awas or Aware (red).]

During October 2010-July 2011 overall activity at Seulawah Agam decreased; seismicity, water temperature, and magmatic gas emissions decreased, but pH measurements were stable and no significant changes at the surface were observed. The volcano was often shrouded in fog during this period. On 11 July 2011 the Alert Level was lowered from II to I.

Beginning on 27 December 2012 (table 3), there was an increase in deep volcanic seismicity over the course of the following week. Visual observations were often prevented due to fog, although on 2 January 2013 scientists observed a new solfatara (a natural volcanic steam vent in which sulfur gases are the dominant constituent, along with hot water vapor) that produced roaring noises and emissions which drifted ˜20 m out from van Heutsz Crater. On 3 January 2013 the Alert Level was raised from I to II; then, on 11 May 2013, the Level was lowered to I.

Weekly Reports - Index

CVGHM reported that seismicity at Seulawah Agam increased during 27 December-2 January. Visual observations were prevented due to fog, although on 2 January scientists observed a new solfatara that produced roaring noises and was within 20 m of van Heutsz Crater on the NNE flank. The Alert Level was raised to 2 (on a scale of 1-4) on 3 January.

CVGHM reported that during October 2010-July 2011 activity at Seulawah Agam decreased. Measurements indicated that seismicity decreased, water temperature decreased and pH levels were stable, gas emissions were lower, and no significant surface changes were observed. The Alert Level was lowered to 1 (on a scale of 1-4) on 11 July.

CVGHM reported that although seismicity from Seulawah Agam fluctuated during April to August 2010, the data reflected increased activity overall. On 1 September, CVGHM raised the Alert Level to 2 (on a scale of 1-4) and restricted visitors from approaching the crater within a 3-km radius.

Information is preliminary and subject to change. All times are local (unless otherwise noted)

This is our first report on Seulawah Agam, which has not erupted since a phreatic eruption in 1839. Beginning in April 2010, the seismicity increased at the volcano (table 1). However, visible signs of unrest were absent, although the volcano often is covered by fog.

Table 1. Types and numbers of volcanic earthquakes recorded at Seulawah Agam during April-August 2010. Background levels prior to increased April activity were not available. Courtesy of CVGHM.

Month

Deep volcanic

Shallow volcanic

Apr 2010

66

70

May 2010

55

121

Jun 2010

53

83

Jul 2010

46

76

Aug 2010

80

99

On 1 September, based on the increase in seismicity, the Center of Volcanology and Geological Hazard Mitigation (CVGHM) raised the Alert Level to 2 (on a scale of 1-4) and restricted visitors from approaching the crater within a 3-km radius.

Seismicity at Seulawah Agam volcano, Indonesia, caused the Center for Volcanology and Geological Hazard Mitigation (CVGHM) to raise the Alert Level from 1 to 2 (on a scale from 1-4) from 1 September 2010 through 11 July 2011. According to historical records, Seulawah Agam last erupted in 1839, although the likelihood and character of that eruption is in debate.

The summit of Seulawah Agam hosts a forested crater ~400 m wide (figure 1). The volcano also hosts several active fumarole fields, such as those in the van Heutsz crater, which sits on the NNE flank at ~650 m elevation (figure 2).

Figure 2. Hazard map of Seulawah Agam. Hazard Zones I-III (from outer to innermost) consist of both circular areas (indicating hazards from material dispersed through the air) and irregularly shaped areas (funneled by topography along the ground). Courtesy of the Center for Volcanology and Geological Hazard Mitigation (CVGHM).

The hazard zones, as with all other monitored Indonesian volcanoes, concern airborne ejected/explosive material (circular zones delineating areas prone to ash fall and/or pyroclastic bombs) and ground-traveling, topographically controlled processes (irregular shaped zones delineating areas prone to lava flows, pyroclastic flows, and/or lahars); each Hazard Zone level (I-III) thus delineates a circular and an irregular area. At Seulawah Agam, the hazard zones are centered at the summit of the volcano. The van Heutsz crater, however, is located outside of the 2 km radius of Hazard Zone III, but within the topographically prone area of Hazard Zone III.

Seismicity increase. Beginning in April through September 2010 seismicity fluctuated at Seulawah Agam, although increased overall, indicating increased activity of the volcano. The Jakarta Post reported that CVGHM recorded 80 volcanic earthquakes during August 2010, the equivalent of nearly 3 volcanic earthquakes per day. On 1 September, CVGHM raised the Alert Level to 2, and restricted access to areas within 3 km of the summit crater (figure 2).

According to CVGHM, seismicity fluctuated at elevated levels from October 2010 through June 2011. In July, seismicity was still elevated above the baseline during October 2010-June 2011. However, the occurrence of shallow volcanic earthquakes was reduced compared to recent trends (table 2).

Table 2. Seismicity at Seulawah Agam during 1 October 2010-10 July 2011. The Alert Level was lowered from 2 to 1 (on a scale from 1-4) on 11 July 2011. Data courtesy of the Center for Volcanology and Geological Hazard Mitigation (CVGHM).

Date

Shallow volcanic

Deep volcanic

Local tectonic

Distant tectonic

Oct 2010-May 2011

12-65 / month

28-116 / month

14-30 / month

55-138 / month

Jun 2011

77 / month

74 / month

15 / month

74 / month

01-10 Jul 2011

12 / 10 days

20 / 10 days

15 / 10 days

20 / 10 days

CVGHM also reported that comparison of data from October 2010 and February 2011 indicated a decline in the emission of volcanic gases, a stabilization of the pH of crater waters, and a decrease in the measured temperature of fumaroles. On 11 July 2011, CVGHM lowered the Alert Level to 1, restricting access only to the summit crater.

Seulawah Agam (also known as Seuleuwah Agam) volcano, one of three active stratovolcanoes in the Aceh province (>5 million inhabitants), is located at the NW tip of Sumatra. Seulawah Agam has two craters, van Heutsz (Heszt), the most active crater at an elevation of 714 m on the N flank, and Simpago on the S flank. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) reported that activity at Seulawah Agam is generally characterized by white plumes rising ˜1 m from the crater. Seulawah Agam has remained non-eruptive through at least 2 January 2013.

Historical data indicated that Seulawah Agam volcano last erupted 12-13 January 1839 on its NNE flank (van Heutsz crater). Prior to that, an eruption occurred in 1510 (˜10 years), also on its NNE flank.

During April to August 2010, the seismic data suggested increased activity overall, with marginal fluctuation. On 1 September 2010, CVGHM raised the Alert Level from I to II and restricted visitors from approaching the crater within a 3-km radius. [The 4-level Indonesian Alert Level Scale is as follows: I - Normal (green); II - Waspada or Alert (yellow); III - Siaga or Standby (orange); and IV - Awas or Aware (red).]

During October 2010-July 2011 overall activity at Seulawah Agam decreased; seismicity, water temperature, and magmatic gas emissions decreased, but pH measurements were stable and no significant changes at the surface were observed. The volcano was often shrouded in fog during this period. On 11 July 2011 the Alert Level was lowered from II to I.

Beginning on 27 December 2012 (table 3), there was an increase in deep volcanic seismicity over the course of the following week. Visual observations were often prevented due to fog, although on 2 January 2013 scientists observed a new solfatara (a natural volcanic steam vent in which sulfur gases are the dominant constituent, along with hot water vapor) that produced roaring noises and emissions which drifted ˜20 m out from van Heutsz Crater. On 3 January 2013 the Alert Level was raised from I to II; then, on 11 May 2013, the Level was lowered to I.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Basic Data

Volcano Types

Rock Types

Tectonic Setting

Subduction zoneContinental crust (> 25 km)

Population

Within 5 kmWithin 10 kmWithin 30 kmWithin 100 km

226
10,555
306,345
1,565,392

Geological Summary

Seulawah Agam at the NW tip of Sumatra is an extensively forested volcano of Pleistocene-Holocene age constructed within the large Pleistocene Lam Teuba caldera. A smaller 8 x 6 km caldera lies within Lam Teuba caldera. The summit contains a forested, 400-m-wide crater. The active van Heutsz crater, located at 650 m on the NNE flank of Suelawah Agam, is one of several areas containing active fumarole fields. Sapper (1927) and the Catalog of Active Volcanoes of the World (CAVW) reported an explosive eruption in the early 16th century, and the CAVW also listed an eruption from the van Heutsz crater in 1839. Rock et al. (1982) found no evidence for historical eruptions. However the Volcanological Survey of Indonesia noted that although no historical eruptions have occurred from the main cone, the reported NNE-flank explosive activity may have been hydrothermal and not have involved new magmatic activity.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Deformation History

There is no Deformation History data available for Seulawah Agam.

Emission History

There is no Emissions History data available for Seulawah Agam.

Photo Gallery

Seulawah Agam, rising above farmlands on its eastern flank, is an extensively forested volcano of Pleistocene-Holocene age located in the province of Aceh at the NW tip of Sumatra. Gunung Seulawah Agam was constructed within the large Pleistocene Lam Teuba caldera and a smaller 8 x 6 km caldera. Wispy clouds drape the summit, which contains a forested 400-m-wide crater. The van Heutsz crater, located at 650 m on the NNE flank, is one of several areas containing active fumarole fields.

Anonymous photo, 1995.

Seulawah Agam, rising above farmlands on its flank, is seen here with the northern coast of Sumatra in the background. This extensively forested volcano of Pleistocene-Holocene age is located in the province of Aceh at the NW tip of Sumatra. Gunung Seulawah Agam was constructed within the large Pleistocene Lam Teuba caldera and a smaller 8 x 6 km caldera. The summit contains a forested 400-m-wide crater.

Copyrighted photo by Michael Thirbeck, 2007.

GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

External Sites

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

The Sentinel Hub Playground provides a quick look at any Sentinel-2 image in any combination of the bands and enhanced with image effects; Landsat 8, DEM and MODIS are also available. Sentinel Hub is an engine for processing of petabytes of satellite data. It is opening the doors for machine learning and helping hundreds of application developers worldwide. It makes Sentinel, Landsat, and other Earth observation imagery easily accessible for browsing, visualization and analysis. Sentinel Hub is operated by Sinergise

Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Seulawah Agam. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.

Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Seulawah Agam. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).